let en is second chose

run_in_main.m

// ref from: http://stackoverflow.com/questions/20241256/ios-app-default-language-en-is-not-applied
// remove what was previously stored in NSUserDefaults (otherwise the previously selected language will be still the first one in the list and your app won't be localized in the language selected in settings)
[[NSUserDefaults standardUserDefaults] setObject:nil forKey:@"AppleLanguages"];
[[NSUserDefaults standardUserDefaults] synchronize]; // make the change immediate

// reorder the languages so English is always the default fallback
NSMutableArray *mutableLanguages = [[NSLocale preferredLanguages] mutableCopy];
NSInteger enIndex = NSNotFound;
for (NSString *lang in mutableLanguages) { if ([lang isEqualToString:@"en"]) { enIndex = [mutableLanguages indexOfObject:lang]; break; } }
@try {
    if ((enIndex != 0) && (enIndex != 1)) { [mutableLanguages exchangeObjectAtIndex:1 withObjectAtIndex:enIndex]; }
} @catch (NSException *exception) {

}
// save the changes
[[NSUserDefaults standardUserDefaults] setObject:mutableLanguages forKey:@"AppleLanguages"];
[[NSUserDefaults standardUserDefaults] synchronize]; // to make the change immediate

return UIApplicationMain(argc, argv, nil, NSStringFromClass([YourAppDelegate class]));